Sap Bro,
you really need to brush up on your history. The founding fathers of USA and for that matter the West, were Christians. Their constituition has its basis also on the ideals of Christianity. Don't forget they take their oath on the Bible. And in their money it is written "In God We Trust". The freedom has also allowed people to take oath on the Bhagwad Gita and Quran. The Atheists have a history of Christianity behind them and very often they retain the goodness of their christian values even as Atheists. 
Religion shapes our culture. The West did not ask us to change our religion but to change our culture to support freedom and tolerance. Many cultures go againsts freedom and tolerance.
Ha HA Ha you said who cares if one changes religion but some time back you were moaning about the fact that Hindus became Christians. Lolz :)